With the increasing demand for water by growth in the nation's population and establishment of new communities, many water producers find it necessary to utilize water sources which are not as desirable as those which were readily available in the past. In addition to the growing need to use such less desirable water sources, many previously good quality water sources have been found to be contaminated with chemicals and bacteria. Pollutants such as sodium, lead, benzene, cyanide, zinc, magnesium, calcium, insecticides, herbicides, asbestos fibers, detergents, nitrates, dioxin, chlorine, various other toxic industrial wastes, algae, bacteria, viruses and even radioactive substances have been identified in aquifers and other water supplies throughout the nation and the world. Furthermore, new chemicals are created each year thereby compounding our water pollution problem even further. Since some pollutants are tasteless, odorless, and invisible they often go undetected for long periods of time. Other pollutants, while presently being deemed safe by some governmental agencies, clearly impart an undesirable taste to tap water and food products prepared using such tap water such as coffee and tea. The expression "but don't drink the water" is no longer merely an amusing remark amongst travelers.
The lower quality of tap water has prompted the demand for purification systems which can be quickly installed in the home or office, or taken along on business or vacation travel. Such purification systems, if they are to be of greatest benefit to people, must be both effective and inexpensive. While many systems are available, there is a continuing need for improvements which will lower the cost of such systems so that a greater percentage of the nation's population can afford such systems. It is an object of this invention to provide components which are inexpensive but still highly effective in water purifying systems, especially smaller units that can be quickly installed in homes or apartments, or motel or hotel rooms by a traveler. It is a further objective of this invention to improve the compactiveness of such water purifying systems by improving the compactiveness of the components thereof.
Some of the small water purification systems which are available for use in the home are small distilling units, activated charcoal, de-ionization devices and reverse osmosis systems. While the improvements of this invention may be used on such systems, the invention is particularly useful on reverse osmosis systems, particularly the smaller of such systems which are especially useful for the home, apartment, laboratories, or traveler who, for health or personal reasons, requires pure water for drinking.
When a solution of different concentrations exists on two sides of a membrane, an osmotic pressure exists which tends to drive solute from the more concentrated side of the membrane, through the membrane, to the less concentrated side. In other words, osmotic pressure tends to adjust the solute concentration on both sides of the membrane so that they are equal. However, if pressure, which exceeds the osmotic pressure of the solution, is applied to the concentrated side of the membrane, solvent will be made to flow through the membrane thereby concentrating the solution even more on the concentrated side and producing a purified solvent on the other side of the membrane. Processes employing this principle are referred to as "reverse osmosis" (sometimes referred to herein as "RO").
Accordingly, it is a further objective of this invention to provide an improvement to components of reverse osmosis water purification systems which can be manufactured inexpensively, which are compact, which can be used with a minimum of maintenance, expense and difficulty, which permits the system to be easily flushed to remove deposits which generally build up in all reverse osmosis units and which facilitates adjustment to the various tap water supply conditions encountered including as for example those experienced by a traveler.
It is also an object of this invention to provide a system which is less subject to malfunction by corrosion, especially corrosion by the concentrate or brine waste stream from RO units.
Some embodiments of this invention are, however, useful for systems and apparatus' other than those directed towards water purification. Thus, other beneficial use of this invention will be apparent to the reader.